The Aim of this proposal is to determine if replication competent but attenuated strains of vaccinia virus can be used as a vector to induce a broad mucosal immune response to inserted genes that encode HIV epitopes. A gene coding for a V3 loop multi-epitope polypeptide will be inserted into a non-essential locus of replication competent, attenuated strains of vaccinia virus. These viruses will be analyzed for expression of the HIV multi-epitope polypeptide and for replication in nasal tissue of infected animals. Animals will be immunized intra-nasally either with virus alone or as part of a prime-boost regime. Systemic, nasal and vaginal immune responses to the HIV multi-epitope polypeptide will be analyzed.